Throw away filters



July 24, 1956 Filed May 28, 1953 M. c. PAVLIC. 2,755,884

THROW AWAY FILTERS 3 Sheets-Sheet l IN VEN TOR.

Mary Pav/ic BY ATTORNEY.

July 24, 1956 M. c. PAVLIC THROW AWAY FILTERS 3 Sheets-Sheet 2 Filed May 28, 1953 nvvazvroa. Mary 6. Pay/1'0 ATTORNEY.

July 24, 1956 M. c. PAVLIC 2,755,384

THROW AWAY FILTERS Filed May 28, 1953 3 Sheets-Sheet 5 IN VENTOR. Mary 6. Pav/ic ATTORNEY.

ted States Patent Oflice 2,755,884 Patented July 24, 1956 THROW AWAY FILTERS C. Pavlic Canton Ohio assignor to The Hoover o mpany, Noi'th Canttin, Ohib, a corporation of Ohio Application May 28, 1953, Serial No. 358,054

2 Claims. (Cl. 183.-51)

This invention relates to suction cleaner filter assemblies and more particularly to a new and mproved throw away paper filter featuring a durable and readily flexible built-in inlet coupling.

In the design and application of inexpensive paper filter bags for upright or floor type suction cleaners, designers have been plagued with the problem of providlng a hght weight, durable and inexpensive mode of coupling the filter bag to the exhaust outlet. It is mandatory that some form of flexible connection be employed since the porous lter paper will not withstand the combined stresses 1mposed by the internal air pressure, the weight of the collected dirt and the continued flexing of the paper Walls adjacent the connection of the filter and cleaner occasioned by the continuous pivotal movement of the propelling handle.

Many expedients have been resorted to heretofore to remedy the problem but none have been entirely satisfactory. Adapter assemblies utilizing rubber bellows couplings will withstand long and rigorous usage but entail certain serious objections including the need for a r1g1d tube and filter clamp at the outlet end of the bellows, considerable additional weight, and excessive cost. A metal hinge is also required between the opposite ends of the bellows to support the lower end of the filterparticularly when a quantity of dirt has collected in the filter.

Other expedients propose the use of flexible conduits and swiveling elbows. These too, increase the overall weight of the cleaner as well as the length of the cleaner. This latter objection is of importance when the handle is raised to its vertical parked position since the reawardly protruding adapter assembly takes up additional room in the storage closet and is subject to damage.

The present invention circumvents these and other disadvantages of prior designs in a simple, highly eifective and inexpensive manner by providing the filter bag itself with a built-in, readily flexible inlet tube. The construction is so inexpensive that it is thrown away along with the filter when the same becomes filled with dirt to its design capacity.

Another feature of the flexible tube is its use to reinforce the inlet end of the filter and to provide an air tight seal therewith.

Accordingly, it is a prime object of this invention to provide a new and improved filter assembly which is inexpensive, light in weight and highly durable.

Another object is the provision of a paper filter bag with a built-in flexible coupling for connecting the bag to the exhaust of a suction cleaner.

A further object is the provision of a filter assembly employing a paper filter bag in which the filter clamping means is mounted directly on the cleaner body at the inlet end of a flexible coupling tube permanently aflixed to a throw away paper filter.

Numerous other objects and advantages of the invention will become apparent from the following detailed specification taken in connection with the accompanying drawings, in which:

Figure 1 is a fragmentary view partly in section of the rear end of a floor type suction cleaner incorporating the invention;

Figure 2 is a view of the throw away filter bag with portions of the inlet end broken away for greater clarity;

Figure 3 is a top view partly in section of the filter adapter and filter clamping means employed to releasably clamp the filter to the suction cleaner, and

Figure 4 is another view of the filter adapter taken along line 4-4 on Figure 3.

Since the novel filter assembly forming the subject matter of this invention may be employed on any floor type suction cleaner, only the rear end portion of a representative type of cleaner has been illustrated. This cleaner, as shown in Figure 1, has a rearwardly opening exhaust air passageway. However, it will be understood that the full advantages of the invention may be enjoyed on a suction cleaner having a laterally opening exhaust air passage.

The suction cleaner generally designated 10 has a main body 11 supporting the usual motor-fan unit. This unit is enclosed by a removable motor hood 12 and has a downwardly opening suction nozzle at its forward end in accordance with common practice. The front end of the main body is supported by a pair of front wheels, not shown, and another pair of rear wheels 13. The propelling handle 14 is provided with a bail 15 at its lower end which straddles motor hood 12 and extends through slots 16 in the main body to interior pivot pins, not shown. It will be understood that the suction inlet of the fan is in communication with the suction nozzle while the exhaust side of the fan opens into the rearwardly extending exhaust air conduit 17.

The principal elements of the filter assembly include an outer appearance bag 18, my unique throw away filter bag 19 and a filter adapter and clamping device generally designated 20. The appearance bag 18 is of the usual cloth type having an opening extending along its lower side from top to bottom and normally maintained closed by a hookless fastener 21. The upper end of the appearance bag is resiliently supported from the propelling handle by a tension spring 22, while its lower end encircles the base of adapter 20 and is removably secured thereto by a band clamp 23.

The filter adapter 20 comprises a very short conduit having a flange 24 at its lower end and having its outer end 40 cut off on the bias. The adapter may be cast integral with the cleaner exhaust but, as herein illustrated, the adapter is removable. Thus, its lower side may be inserted behind a detent clip 25 on the cleaner exhaust. A flange 26 projecting from the upper side of the adapter cooperates with a pivoted latch lever 27 carried by the cleaner body in a manner to lock the adapter rigidly to the cleaner. The latch lever is pivoted upwardly away from the cleaner to release the adapter.

The flexible filter inlet tube may be clamped to the adapter in any suitable manner. The clamp illustrated comprises a wire spring 28 encircling the adapter and lying at an angle to its axis, and preferably, in a plane parallel to the inclined end 40. The opposite ends of the clamp terminate on the upper side of the adapter tube and are bent in the manner illustrated to encircle pin 29 anchored to the adapter tube. A manually operable lever 30 is also pivoted to pin 29 and its underside is provided with converging, cammed flanges 31 which engage the sides of the clamping ring 28 in a manner to constrict the clamp into tight engagement with the filter inlet tube when lever 30 is in the closed position shown. When lever 30 is opened upwardly, the wire spring is free to expand under its own resiliency away from clamping engagement with the filter inlet. In so doing, the ends of the clamping ring move away from one another along pin 29. A light leaf spring 32 is connected to the underside of clamping ring 28 and assures thatthis portion of the clamp will also move away from clamping engagement with the adapter. Spring 32 also holds the clamp in its'proper inclined position at all times.

Referring now more particularly to Figures land 2, it will be seen that my throw away filter bag 19 comprises a tubular paper envelope having inwardly extendpleats 33 along its opposite lateral side. The upper end 33 of the filter is turned over and sealed to one of the fiat sides of the bag.

The combined inlet and flexible coupling for the filter is secured to the opposite lower end of the filter and comprises a pair of very thin walled resilient tubes 34 and 35. Preferably, these tubes are of thermoplastic material which fuses when heated, Tube 34 is of slightly greater diameter than tube 35 in order that the pleated inlet ends of the filter bag may be sandwiched betweenthe two tubes, as clearly indicated in'Figure 2. The two tubes overlap for a distance of one to two inches, or in an area suflicient to form a heat-sealed joint with the paper filter. The smaller diameter tube 35 projects upwardlyinto'the body of the bag and cooperates with theadjacent'lower wall portions of the bag to provide a dirt trap. The other tube 34 projects downwardly beyond theend of the inner tube and beyond the end of the filter bag proper to provide a readily flexible tubular coupling with the exhaust end of adapter 20. Preferably, the inlet of tube 34 is cut 05 on the bias as shown at 36 and is also notched at 38 to mate with a polarization lug 39 cast integral with the top side of the adapter tube. Notch 38 and polariza tion lug 39 assure that the filter will be properly assembled on the adapter with the pleats lying on the opposite sides of the cleaner and with the bias cuts of the adapter and flexible tube overlapping to a maximum degree.

Obviously, the filter bag itself may be formed in various ways and, in particular, the inlet end may be gathered in various manners to fit between tubes 34 and 35. However, one particularly effective and preferable manner of gathering the lower end of the filter is that illustrated in the drawings and more particularly described in my copending application for Letters Patent Serial No. 358,053 filed simultaneously herewith. While tubes 34 and 35 may be joined to the filter by gluing or stitching a more satisfactory and far less expensive joint is formed by applying pressure and heat to the opposite sides of the overlapped tubes in a manner to fuse the plastic material to the paper. This forms an extremely strong bond with the paper which is absolutely air tight. This sealing and bonding operation may be performed by the apparatus described in the aforesaid copending application.

The assembly of the filter to the cleaner will be quite obvious from the foregoing description. The handle may be placed in its vertical parked position after which the hookless fastener 21 for the appearance envelope is opened. Clamping lever 30 is also opened so that tube 34 can be telescoped over the end of the adapter and beneath clamping wire 28. The clamping lever is then closed to lock the filter in place and hookless fastener 21 is closed. The cleaner is then ready for operation. As the cleaner is propelled over the floor being cleaned, the filter assembly will pivot with the handle and the filter bagand itsenclosingenvelope 18 will move in unison with the handle. No flexing will occur in the paper since the required flexing is confined to the portions of the readily flexible plastic tube 34 located between the end of the adapter and the joint with the filter bag. As the dirt is separated within the bag it collects in a ring surrounding the inner, dirt trap endof tube 35.

After the filter bag has been filled to capacity, it is quickly removable from the cleaner by opening the appearance "bag and clamping ring 28 thereby releasing the filter fo'r 'remo'val and disposal. The dirt filled bag is then replaced by a new filter bag in the same manner described above.

While I have shown and described but one embodiment of my invention, it is to be understood that this embodiment is to be taken as illustrative only and not in a limiting sense. I do not wish to be limited to the particular structure shown and described but to include all equivalent variations except as limited by the scope of the claims.

l. A paper filter bag for use on a suction cleaner comprising, a tubular main filter body formed of air pervious paper stock, one end of said tube being gathered to form an inlet of smaller diameter than the body pornon thereof, a-"thin-walled thermoplastic tube extending through said gathered inlet into the interior of said filter body, a second thin-Walled thermoplastic tube having its outlet end telescoped over the exterior of said inlet and bonded to underlying portions of paper and forming the inlet end of said filter, said second tube being flexible and extending beyond the inlet to a point spaced a sufii cient distance therefrom to provide a flexible tubular air conduit secured to and leading into the interior of said filter.

2. A throw away paper filter bag comprising, an elongated tubular envelope of air pervious paper stock, the opposite sides of said filter having pleats extending substantially the full length thereof, means permanently closing'the upper end ofsaid filter, means forming a flexible tubular inlet for the lower end of said filter, said tubular inlet comprising a pair of thin walled flexible tubes having their opposite ends arranged in overlapping relation with the lower inlet end of said filter therebetween so that one tube projects upwardly into the interior of said bag to form a dirt trap therewithin and so that the other tube projects downwardly below said inlet to'provide a flexible conduit leading to said filter inlet, the overlapping portions of said tubes being bonded to said filter inlet in an air tight manner.

References Cited in the file of this patent I UNITED STATES PATENTS v1,907,335 Riebel May 2, 1933 7 2,085,702 Kitto June 29, 1937 2,406,697 Lincoln Aug. 27, 1946 2,521,985 Lang et al Sept. 12, 1950 2,566,275 White Aug. 28, 1951 2,580,630 White Jan. 1, 1952 2,580,665 Dunning et al. Jan. 1, 1952 2,641,333 Woessner June 9, 1953 

